EP2540487B1 - Pressed sheet or continuous ribbon with a sandwich structure, Process to manufacture such pressed sheet or continuous ribbon and Process to manufacture punched material using such pressed sheet or continuous ribbon - Google Patents

Description

The invention relates to a press plate or endless belt, consisting of a carrier body and an embossing body for embossing materials, in particular wood materials or plastic materials by means of a surface structuring of the embossing body, wherein the carrier body is connected to the embossing body via an adhesive, and a method for producing such a press plate or endless belts and production processes for embossed materials using them.

Press plates or endless belts are required to press wood-based panels with decorative and / or overlay papers. This involves a full-surface coating of the wood-based panels with Aminoplastharzfilmen, also called Duroplastharze. Processing takes place, for example, in one-day short-cycle presses or multi-daylight presses. The finished press plates or endless belts are used in the presses to impart a desired surface structure to the wood materials to be produced. Preferably, in this case a congruent embossing is preferred. This means that a decor paper used is used with a conformable press plate or an endless belt, so that the structure of the decorative paper can be embossed into relief in the surface. The structures used in this case may be of natural origin, for example the imitation of a wood pore structure or rock surface, it is also possible to produce any desired structures according to customer requirements.

The decorative and overlay papers used are preferably made of thermoset resins, which pass through pressure and temperature in the press line in a liquid form and enter into a solid connection with the wood material with increasing degree of crosslinking, with simultaneous increase in resin viscosity in the final state. Among the thermoset resins used are the melamine, phenolic or melamine / urea resins, which are known as have been found particularly suitable. During the pressing process, the melamine resin becomes liquid under pressure and temperature, and a further polycondensation takes place. Press time and temperature determine the degree of crosslinking of the melamine resins and their surface quality. After the pressing time, the melamine resin has the desired degree of crosslinking and has turned into a solid phase, wherein a lifelike, the surface of the embossing tool reproducing surface design is achieved by the effected simultaneously structured embossing of Melaminharzaberfläche.

According to the state of the art embossing tools in the form of press plates or endless belts made of steel sheets, which receive the required surface structure by appropriate processing. For this purpose, various methods are known, for example, by orders of a screen printing process to provide an etch resist to make a subsequent etching of the press plate. The sheets used in this case have a very large format, so that it depends on a very precise processing and in particular a cover-compliant further processing, as far as several steps are necessary. Several work steps always occur when particularly deep structures have to be etched and for this purpose several etching operations with a previously applied etching resist are required. In the etching processes, all regions which are to form the raised surface structure later are covered by the mask, so that a surface etching takes place only in the regions which can be attacked directly by the etching liquid. The etched out areas then form the profile valleys of the desired structure, after completion of the etching process the surface is cleaned and in particular the mask is removed.

Alternatively, it is possible to apply a photo layer, which is then subjected to an exposure to the final Development of the photo-layer to subject the press plates or endless belts after the whereabouts of a portion of the photo-layer as an etching resist an etching process. The reproducibility of the masks produced in this way is very difficult and problematic because the Ätzresistschichten to be applied must always be placed exactly in the same position when particularly deep structures are to be etched.

Furthermore, it is known from the prior art, instead of a Siebdruckverfährens to produce a mask by waxing or alternatively to use a UV varnish, which is printed by means of a digital printing process directly on the press plates and endless belts to be processed. After etching, which may need to be repeated several times, particularly deep structures can be achieved here, which are congruent by the application of the digitized printing process to a high degree.

As a further alternative, it is known from the prior art to produce the required structure directly on the surface with the aid of a laser method, wherein the depth structures to be produced are produced directly with the aid of a laser. Also in this method, the exact control of the laser is made with the help of a digital printing technology, so that after completion of the press plates or endless belts these have a 100% match with the decor papers. It is only through the recently developed surface structuring process that the required level is achieved in order to achieve the highest level of conformity of the required press sheet structures with the decor papers.

After completion of the press plates or endless belts, these further process steps can be subjected to achieve special effects, for example, to influence the gloss level. The degree of gloss can be made from matt, semi-glossy to glossy Pressing the wood-based panels have a desired surface texture with gloss effect that comes very close to that of grown natural wood. Preferably, wood pore structures are produced by these methods, but equally imaginative surface designs can be made or a leather imitation, tiles or natural stone surfaces can be reproduced. Any conceivable structure can be produced by this method.

Depending on the intended use of the wood-based panels produced, for example in the wall area, but also in the floor area, the overlay papers can be doped with abrasion-resistant particles, such as corundum, so that a high abrasion resistance is present for the end user. However, this abrasion resistance leads to negative effects on the used press plates or endless belts. After each pressing operation and opening of the presses, a relative movement takes place between the processed wood material with the pressed surfaces and the press plate or endless belt, so that a gradual deterioration of the surface structure occurs. In such a case, it is necessary to completely rework the press plate or to replace it with a new press plate. In the coating, for example of HDF (high-density fiberboard) plates, the press plates must be refurbished after a relatively short period of use. The reason is the high proportion of corundum which is used in the melamine resin films for abrasion resistance, whereby the chrome-plated surfaces are abraded relatively quickly. The production of a press plate is very complex and costly, with a scrapping is provided at the end of the term. Among other things, this is due to the fact that the blanks of the press plates or endless belts are first provided with a direction-free intermediate sanding and additionally polished before the surface structuring, before a new structuring can take place so that gradually after several reworking the thickness of the press plates or endless belts no longer required level reached. Only then follows the complex structure production, for example by the classical etching method, application of the etching reserve, etching with, for example, ferric chloride, full-grade production by, for example, sandblasting and subsequent surface sealing, for example chromium plating, or alternatively by the production of the structure by means of a laser engraving. Likewise, mechanical damage usually requires the press plate surfaces to be completely abraded and reworked. The result of this is that the relatively expensive base press sheets only remain conditionally usable and must be scrapped after approximately four to six work-ups, since they become too unstable due to their thickness and can not be uniformly fixed in the press installation.

From the WO 2011/051116 A1 For example, a method for producing a press plate is known in which a press plate blank is brought into a hollow cylindrical shape in order to subsequently fix it to a carrier. The carrier may be, for example, a cylinder, so that the further processing steps can be carried out by rotation. Subsequently, the press plate blank is re-formed into a flat press plate to then make an attachment to a carrier plate with the aid of an adhesive. The use of a pure adhesive is considered to be critical at the temperatures to be provided of up to 230 degrees, so that the adhesion of the press plate blank on the support plate can not be guaranteed permanently.

From the DE 10 2007 062 123 A1 For example, a mold for producing a microstructure is known. This mold is primarily used for clamping on a roller and consists of a carrier film on which an embossing lacquer is arranged. The surface of the embossing lacquer in this case has elevations and depressions in the desired microstructure and is used for embossing of the materials provided. In order for the carrier film can be held on the roller, is preferably a Clamping cylinder used, but also not excluded that the attachment of the carrier film can be done by an adhesive or a magnetic attachment.

From the WO 2006/136949 A2 For example, there is known a method of manufacturing floor panels using a press tool consisting of a frame and individual removable press plates. The press plates can be held by screws, an adhesive or possibly magnets.

However, the methods known from the prior art do not solve the problem of heat transfer to the material plates to be processed or do not ensure sufficient extent that the adhesive effect is ensured even at higher temperatures of up to 250 degrees.

The invention has for its object to provide a novel press plate or endless belt for a single or multi-daylight press, which allows replacement of a stamping body with sufficient heat transfer.

This object is achieved by a press plate or endless belt according to claim 1, a method for producing a press plate or endless belt according to claim 12 and a method for producing embossed Werkstoffegemäss claim 15.

Compared to the previous method with a base material which forms the press plate or endless belt and which with a surface structuring is provided, it is proposed according to the invention to use a carrier body which is connected to an embossing body via an adhesive, wherein only the embossing body has a surface structuring. Thus, the embossing body can be produced inexpensively regardless of the carrier body and be connected by the adhesive with the carrier body insofar that a proper use for single or multi-day presses can be done. After wear of the surface structuring, it is possible subsequently to remove the embossing body from the carrier body and replace it with a new embossing body. The material required in this case is significantly reduced because the carrier body can be used over and over again and only an extremely thin coating in the form of an embossing body must be replaced.

For this purpose, the carrier body, consisting of, for example, stainless steel, for example AISI No. 630, AISI 410 or AISI 304 or brass according to the prior art, is first prepared. Instead of the usual surface structuring of the press plate or endless belt by means of an etching technology or a digital laser engraving, the embossing body is produced independently of the carrier body, that is provided with a surface structure, Subsequently, the carrier body and the embossing body with the aid of a magnetic adhesive are intimately and reversibly connected so that a sandwich structure is created. This sandwich structure has the particular advantage that in later work-up the expensive carrier body is retained and only the upper embossing body has to be renewed. By this measure, production and raw material costs are saved to a considerable extent. Furthermore, the embossing body, which is usually much thinner and cheaper than the carrier body, already prefabricated and placed in storage for each customer. This saves time and significantly shortens delivery times.

In an embodiment of the invention it is provided that the adhesive consists of magnetic materials. Such adhesives are always suitable when the carrier body and the embossing body are both made of steel and thus have magnetic properties. To connect the carrier body and embossing body is a high temperature resistant magnetic film is used, which ensures the adhesive bond as the intimate connection between the two bodies and consists of a crosslinked silicone elastomer, with an addition of high temperature resistant magnetic materials, such as samarium / cobalt, aluminum / nickel / cobalt, neodyn / Iron / boron, barium or strontium ferrites or soft ferrites, such as manganese / zinc. All of the aforementioned permanent magnet materials lose very little of their holding power, about 15 to 20% at the existing operating temperatures of about 220 °. The proportion of additional magnetic materials depends on the respective desired adhesive force of the materials, less the loss of adhesion at the respective operating temperature and the total weight of the embossing body. However, these boundary conditions can be taken into account without problems, so that even with the help of a magnetic film, a permanent, but reversible connection between the carrier body and the embossing body can be produced. At the same time, the magnetic film offers the possibility of separating both bodies from each other without residue, so that a rapid exchange of the embossing body can take place in the event of wear.

If high-temperature-resistant adhesives doped with metal powder are to be used, modified acrylate adhesives, for example PMMA adhesive poly (methacrylic methacrylate), PMt poly (methacrylimide), MBS poly (methacryl methacrylate) styrene butadiene, UP unsaturated polyester resins are suitable - DAP diallyl phtatlate, aromatic polyimides, silicone resins, epoxy resins, ACM acrylate rubber or FKM fluorinated rubber adhesive.

To the heat transfer value of the press plates or endless belts according to the invention, a heating of the material plates is in the on or To increase multi-floor presses, the adhesive is doped with a metal powder, for example, copper, brass, aluminum or iron. The adhesives used in this case can be used up to temperatures of 250 ° Celsius, so that premature detachment of the embossing, for example, at the temperatures occurring for the production of the material plates of about 220 ° does not occur. At the same time, however, the adhesives can be tempered above temperatures of 250 °, so that the embossing body can be detached from the carrier body without further ado.

For the production of the embossing body known from the prior art, for example, etching technology or laser engraving, used, these preferably have only a small thickness and thus can be processed much less complicated. One possibility for this is to clamp a stamping body in the form of a metal foil or thin sheets on a steel cylinder for surface structuring, the diameter of the steel cylinder is adaptable to the maximum width of the press plates, so after completion of the embossing body and after removal of the Stahlzylindem this with the Carrier body can be connected.

As far as metal foils or thin sheets or other materials, such as steel or brass are used, they can be clamped onto the steel cylinder and then engraved accordingly, followed by the above steps until the completion of the surface structuring. The metal foils or thin sheets produced in this way are then cut to the size of the carrier body and connected to it, so that the press plate or endless belt is available for further use.

Alternatively, it is possible to electroplate a ballard skin of about 100 microns on a copper base layer, wherein between the base layer and the ballard skin can be arranged a release layer, so that a later lifting of the ballard skin is possible. With ballard skin, gravure refers to a peelable layer of copper on a gravure cylinder. The gravure cylinder made of steel covers a 2 mm thick base copper layer on which a second copper layer, the so-called ballard skin, is galvanized. Between the 100 μm thin ballard skin and the main body lies the separation layer, so that the ballard skin can be easily removed after engraving and replaced with a new one. After galvanizing the copper layer, it can still be polished and then the surface structuring takes place, for example by means of a laser. The finished engraved surface is then coated to increase the wear resistance galvanic with a chrome layer, in individual cases, further processing steps can follow, for example, to influence the gloss level. To remove the ballard skin this is usually opened at a front end of the steel cylinder and then pulled down by pliers and removed. The steel cylinder itself can then be reused for the next production.

For the carrier body, a metal is preferably used, for example stainless steel, AISI No. 630, AISI 410 or AISI 304 or alternatively a brass sheet. In contrast, the embossing body may consist of copper, brass or stainless steel, wherein the thickness is freely selectable depending on the required structure depth, preferably 0.3 to 3.0 mm, particularly preferably 0.3 to 1.5 mm.

The main advantages of the newly designed press plates or endless belts consists in a later separation of carrier body and embossing body, the embossing body is exposed to significantly higher wear than the carrier body, the carrier body can therefore be used several times and is always new with a stamping body connected, preferably with magnetic materials doped pressure-sensitive adhesives are used, which allow an intimate connection. Alternatively, a connection can be made with the aid of magnetic materials, in particular a magnetic adhesive film, in order to achieve the desired advantages.

The method according to claim 12 is characterized by a particular economy and also allows multiple reuse of the carrier body, which is exposed to almost no wear. The embossing bodies used in the form of a thin metal foil or a thin sheet can be reversibly removed from the carrier body, so that a workup of the carrier body is required only to a small extent. As a result, considerable processing time is saved and also a considerable savings potential is achieved by the use of thin sheets or metal foils with a surface structuring, in particular due to the fact that the materials to be processed, wood materials with overlay and decor papers cause wear of the embossing body. The particular advantage results from the reversible connection of carrier and embossing body.

A further advantage of the press plates or endless belts according to the invention is that less high-quality metals are used for the carrier body and thus the production costs can be significantly reduced. So far, it has been necessary to use high-grade stainless steels, which make it possible to carry out the necessary surface structuring. However, there is no need to be taken into account, since the surface structuring takes place only on the surface of the embossing body.

The invention will be described again with reference to two figures.

Fig. 1

in einer perspektivischen Ansicht ein hergestelltes Pressblech mit einer Holzporenstruktur und

Fig. 2

in einer vergrößerten Schnittdarstellung den Aufbau des Pressbleches.

It shows

Fig. 1

in a perspective view of a manufactured pressed sheet with a wood pore structure and

Fig. 2

in an enlarged sectional view of the structure of the press plate.

FIG. 1 shows a perspective view of an inventive press plate 1, which is flat in the embodiment shown. In the case of an endless belt, however, this embossing tool can also be curved. The press plate 1 shows a grain 2, which is modeled, for example, the shape of a wood pore structure. However, it is conceivable that other grain or other surface textures in this Way is produced by the inventive method and the necessary etching or laser process.

FIG. 2 shows in an enlarged side view part of the front edge region of the press plate 1 and the surface structuring thereon. As in particular from FIG. 2 As can be seen, the press plate 1 consists of a carrier body 10, an embossing body 11 and an adhesive 12. The adhesive 12 allows, as far as it consists of a doped with metal powder high temperature resistant adhesive or a magnetic film, a detachment of the embossing body 11 of the carrier body 10. The carrier body 10th Thus, it can be reused while, on the other hand, a worn embossing body 11 is replaced. The existing on the embossing body 11 surface structuring 13 is prepared for example by means of known etching technologies or a laser engraving, wherein a layer thickness of the embossing body of 0.3 to 3 mm, preferably 0.3 to 1.5 mm is used. For the production of the embossing body 11 it is possible aufzuspannen this on a steel cylinder to produce the surface structure 13 by an etching technology or a laser process and after preparation and further treatment, such as chrome plating and other steps to influence the gloss level after removal from the steel cylinder, with the help the adhesive layer 12 to connect to the carrier body 10.

A particular advantage of this invention press plates or endless belts is that for the carrier body 10 less high-quality metals must be used and thus the production costs can be significantly reduced. So far, it has been necessary to use high-grade stainless steels, which make it possible to carry out the necessary surface structuring. However, there is no need to be taken into account, since the surface structuring takes place only on the surface of the embossing body.

LIST OF REFERENCE NUMBERS

1

press plate

2

Grain

10

support body

11

stamping body

12

adhesives

13

surface structure

Claims (15)

1. Pressing plate (1) or continuous belt, consisting of a carrier body (10) and an embossing body (11) for embossing materials, in particular wood materials or plastic materials, by means of a surface structuring of the embossing body (11), wherein the carrier body (10) is connected to the embossing body (11) via an adhesive agent (12), characterized in that, in case of carrier (10) and embossing bodies (11) made of steel, the adhesive agent (12) consists of a magnetic foil with high temperature stability, or that the adhesive agent consists of an adhesive with high temperature stability doped with metal powder which may be employed up to temperatures of 250 °C and is tempered above temperatures of 250 °C for detachment.
2. Pressing plate (1) or continuous belt according to claim 1, characterized in that the carrier body (10) and the embossing body (11) form a sandwich structure which is reversibly interconnected.
3. Pressing plate (1) or continuous belt according to claim 1 or 2, characterized in that the magnetic foil consists of a silicone elastomer to which magnetic materials with high temperature stability have been added, such as samarium/cobalt, aluminium/nickel/cobalt, neodymium/iron/boron, barium or strontium ferrites or soft ferrites, such as manganese/zinc compounds.
4. Pressing plate (1) or continuous belt according to one of claims 1, 2 or 3, characterized in that an adhesive with high temperature stability and doped with metal powder is applicable, for example acrylate adhesive, such as PMMA adhesive poly(methacryl-methacrylate), PMI poly(methacrylimide), MBS poly(methacryl-methacrylate)-styrene-butadiene, UP unsaturated polyester resins - DAP diallyl phthalate, aromatic polyamides, silicone resins, epoxy resins, ACM acrylate rubber or FKM fluororubber adhesive.
5. Pressing plate (1) or continuous belt according to one of claims 1 to 4, characterized in that copper, brass, aluminium or iron may be used as metal powder.
6. Pressing plate (1) or continuous belt according to one of claims 1 to 5, characterized in that the bonding of the adhesive agent (12) may be cancelled by a solvent.
7. Pressing plate (1) or continuous belt according to one of claims 1 to 6, characterized in that the embossing body (11) is embodied as Ballard shell, for example as strippable copper layer.
8. Pressing plate (1) or continuous belt according to one of claims 1 to 7, characterized in that the Ballard shell consists of metal foils or thin sheets which are mounted on a steel cylinder for surface structuring, wherein the diameters of the steel cylinders may be adapted to the maximum width of the pressing plates (1).
9. Pressing plate (1) or continuous belt according to one or several ones of claims 1 to 8, characterized in that the Ballard shell of about 100 µm is electroplated onto a copper base layer, a separation layer being disposed between the two layers.
10. Pressing plate (1) or continuous belt according to one of claims 1 to 9, characterized in that the carrier body (10) consists of a metal, preferably of stainless steel, for example AISI No. 630, AISI 410 or AISI 304, or brass, and/or that the embossing body (11) consists of copper, brass or stainless steel, wherein the thickness may be selected depending on the structure depth, preferably 0.3 to 3.0 mm, particularly preferred 0.3 to 1.5 mm.
11. Pressing plate (1) or continuous belt according to one or several ones of claims 1 to 10, characterized in that the surface structuring of the embossing body (11) is accomplished before it is connected to the carrier body (10) and/or that the surface structuring of the embossing body (11) may be produced by etching methods or laser engraving methods.
12. Method for manufacturing a pressing plate (1) or continuous belt for embossing materials, in particular wood materials or plastic materials, comprising a carrier body (10) and an embossing body (11), wherein

    - the embossing body (11) obtains a surface structuring by an etching method, rolling method, pressing method or laser engraving,

    - the carrier (10) and embossing body (11) is connected with an adhesive agent (12), wherein in case of carrier (10) or embossing bodies (11) made of steel, the adhesive agent (12) consists of a magnetic foil with high temperature stability, or that the adhesive agent consists of an adhesive with high temperature stability doped with metal powder which may be employed up to temperatures of 250 °C and is tempered above temperatures of 250 °C for detachment.
13. Method according to claim 12, characterized by a reversible connection of the carrier (10) and embossing body (11).
14. Method according to claim 12 or 13, characterized by an embossing body (11) which is, for surface structuring, mounted or has been electroplated on a metal cylinder and is connected to the carrier body (10) after it has been peeled off the metal cylinder.
15. Method for manufacturing embossed materials, in particular wood materials or plastic materials, by means of a pressing plate or continuous belt, consisting of a carrier body (10) and an embossing body (11) with a surface structure which are interconnected by an adhesive agent, wherein in case of carrier (10) and embossing bodies (11) made of steel, the adhesive agent (12) consists of a magnetic foil with high temperature stability, or that the adhesive agent consists of an adhesive with high temperature stability doped with metal powder which may be employed up to temperatures of 250 °C and is tempered above temperatures of 250 °C for detachment.

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